1. Technical Field
Example embodiments of the present invention relate in general to frequency control, and more specifically to a method of controlling an uplink frequency that can be used in mobile communication or wireless communication, and a terminal device using the same.
2. Related Art
In recent times, an orthogonal frequency division multiple access (OFDMA) method or a single carrier-frequency division multiple access (SC-FDMA) method are being adopted in a variety of mobile communication technologies. IEEE 802.16, 802.20 of a portable Internet system and a standard of a Wibro system adopt the OFDMA method, and a cellular communication system referred to as long term evolution (LTE) adopts the OFDMA method and the SC-FDMA method in a 3rd generation partnership project (3GPP).
In a mobile communications system, Data is loaded into a radio frequency (RF) central frequency to be transmitted. In particular, in a case in which the OFDM method and the SC-FDMA are used, noise occurs in all packets transmitted when the RF central frequency does not exactly correspond between Tx and Rx, unavoidably deteriorating system performance. Therefore, in such a communication system, technology is generally used that transmits a prearranged reference signal in a particular resource space (specific frequency and specific time) so as to measure channel distortion and compensate for the measured distortion to eliminate noise occurring overall in the data.
In existing technology developed for a relatively low-speed mobile environment, even when a frequency offset is detected only in a downlink and the same value of frequency compensation applied to the downlink is applied to an uplink in order to compensate for channel distortion, compensation for channel distortion was possible without any problems. However, in a high-speed mobile environment, such a method in which the compensation value of the downlink is equally applied to the uplink becomes problematic due to the Doppler effect.